This invention relates generally to radio signal amplification for broadband wireless data communication and specifically to powering such devices. Typical wireless network systems comprise one or more access devices for communication purposes. Users communicate with each other and access data with wireless communication devices including desktop and portable computers, personal digital assistants, cellular telephones and other wireless devices.
Wireless data communications generally follow one or more of the standards promulgated by industry organizations, such as the Institute of Electrical and Electronic Engineers (IEEE) standards 802.11a, 802.11b, and 802.11g. These standards, and the Federal Communications Commission (FCC) regulations that govern the frequency bands that such standards use, restrict the power of radio signals that carry the data, thus limiting the physical area over which signals can be reliably transmitted and received. For large buildings, and particularly office buildings having steel-beam construction that may inhibit radio wave propagation, wireless data systems often require multiple transmitters or “access points” and amplifiers to ensure usable signal strength in the desired coverage area. To maintain optimum coverage, the access points or amplifiers must be controlled to provide a constant output.
The placement of such multiple access points and amplifiers has typically required multiple cables to carry both the data signal and the required power to the transmitting device. This complicates the already difficult task of retro-fitting wireless systems in completed structures. For instance, the requirement to provide an electrical power supply to the access point or amplifier may be complicated by the lack of standard power outlets in the required areas and the building code requirements that are invoked if new power wiring must be installed.
The present invention mitigates these complexities by providing multiple sources of power for access points and amplifiers via existing Ethernet cables or radio antenna cables by use of a power injection devices, or alternatively, by direct connection of the appropriate DC voltage. A method is also provided to enhance the control of constant output amplifiers to maximize signal strength and coverage as well as minimizing installation complexity.